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Evacuees from the west side of Fukushima receive radiation scans in this photo taken in March.

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Evacuees from the west side of Fukushima receive radiation scans in this photo taken in March. 03:36

Story highlights

Radiation from cell phones can possibly cause cancer, WHO announced in May

A listeria outbreak in cantaloupe killed 30 people and sickened nearly 150

This year also marked the 40th year since Congress passed the National Cancer Act of 1971

Other big stories: Health care reform, head injuries in the NFL

The most deadly recorded listeria outbreak and concerns about nuclear radiation after Japan's biggest earthquake made major health headlines this year, along with several notable deaths to cancer and the inspiring recovery of a Congresswoman who suffered brain injuries from a gunshot wound.

Here's a look back at some of the top stories of 2011, a year that marked major anniversaries in some of the world's most pernicious diseases -- HIV/AIDS and the "war" on cancer.

A congresswoman's recovery

2011 was barely a week old when shots rang out in a grocery store in Tucson, Arizona. U.S. Rep. Gabrielle Giffords, 40, had been shot in the head by a gunman.

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'Cold shutdown' achieved at Fukushima

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Cause of listeria in cantaloupe discovered

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Cause of listeria in cantaloupe discovered 02:42

Nuclear fears in Japan

An 9.0-magnitude earthquake, the most powerful one to hit Japan in recorded history, led to a tsunami that engulfed parts of Honshu. It also started a meltdown at the Fukushima Daiichi's nuclear facility in northeast Japan.

Subsequent tests have detected radiation in a sample of people who live around the power plant.

Although the Japanese workers were able to achieve a "cold shutdown" at the plant in mid-December, experts say it will take perhaps decades to fully clean up the nuclear disaster. What this entails for people who live around the site remains unclear.

A listeria outbreak in cantaloupe killed 29 people and sickened nearly 150 in the United States, making this year's outbreak the deadliest for listeria since the Centers for Disease Control and Prevention began keeping track. One woman pregnant at the time of illness had a miscarriage, according to the CDC.

The outbreak first detected in September was traced back to a Colorado farm. Unsanitary conditions at the farm's packing facility are a possible contributing cause, the U.S. Food and Drug Administration said in October.

The U.S. Preventive Services Task Force gave the PSA test a "D" rating, meaning it offers "no net benefit or that the harms outweigh the benefits."

The issue is that many of the prostate cancers that get detected are so small and slow-growing that they'll never be harmful. The screening does not determine whether the cancer is a harmful one versus the slow, harmless ones.

Most men who learn they have prostate cancer receive invasive treatment for a disease that might not have affected their health. At the same time, prostate cancer survivors say their lives were saved by the screenings.

It was the 30th anniversary of HIV/AIDS. The first report of the disease appeared on June 5, 1981, in the Center for Disease Control's Morbidity and Mortality Weekly Report.

Although medicine and treatment has been greatly advanced since the 1980s, the disease has killed more than 25 million people worldwide. Today, about 33 million are living with HIV/AIDS, with more than a million of those in the United States.

The toll of repeated head blows and injuries loomed over football again.

One former football player killed himself after leaving a message telling his family to get his brain to the NFL brain bank. An examination of his brain showed that he had signs of a brain disease found in athletes who have been exposed to repeated brain trauma.

Finally, the health care reform law signed into law by President Barack Obama last year went through several legal challenges in 2011 and will head to the Supreme Court in 2012.

The Patient Protection and Affordable Care Act was passed in March 2010 by a Democratic congressional majority with the support of the president. The law faces legal challenge from 26 states, led by Florida. Those appeals have paved the way to a hearing in the Supreme Court.

This year, the CDC reported that about 2.5 million young people have received health insurance coverage as a result of health care reform measures.